What are the guidelines for managing a patient with diabetic foot and a history of peripheral arterial disease (PAD)?

Management of Diabetic Foot with Peripheral Arterial Disease

Patients with diabetic foot and PAD require immediate vascular assessment, prompt infection management with interdisciplinary team referral, and comprehensive preventive foot care including patient education, biannual clinical foot examinations, and appropriate footwear to prevent amputation. 1

Immediate Assessment Priorities

Vascular Evaluation

• Assess pedal pulses (dorsalis pedis and posterior tibial) at every visit 2
• If both pulses are palpable, this generally excludes significant PAD 2
• Obtain ankle-brachial index (ABI) and Doppler arterial waveforms in all patients with foot ulcers 2
• ABI of 0.9-1.3 with triphasic waveforms largely excludes PAD 2
• Severe ischemia (ABI <0.5 or ankle pressure <50 mmHg) requires urgent vascular imaging and revascularization 2
• Critical pitfall: Do not rely solely on ABI in diabetics—arterial calcification causes falsely elevated readings; always correlate with pulse exam and consider toe pressures or TcPO2 2

Infection Screening

• Maintain high index of suspicion for foot infection, as PAD plus infection confers nearly 3-fold higher amputation risk than either alone 1
• Suspect infection if patient presents with: local pain/tenderness, periwound erythema, edema, induration, purulent discharge, foul odor, visible bone, probe-to-bone positive, or systemic inflammatory signs (fever >38°C or <36°C, tachycardia >90/min, tachypnea >20/min, WBC >12,000 or <4,000/mcL) 1
• The presence of diabetes with peripheral neuropathy and PAD makes infection presentation more subtle—absence of typical signs does not exclude infection 1

Neuropathy Assessment

• Test for loss of protective sensation using 10-g monofilament at 2 of 3 sites: plantar heel, metatarsal heads, and toe tips 1, 2
• Perform additional neurological testing: pinprick, temperature, vibration (128-Hz tuning fork), and ankle reflexes 1
• Loss of protective sensation dramatically increases ulceration risk and is present in 78% of diabetic foot ulcers 1

Infection Management Algorithm

When Infection is Present

• Refer immediately to interdisciplinary care team for prompt diagnosis and treatment to avoid amputation 1
• Deep soft-tissue infection requires prompt surgical drainage, followed by vascular imaging and expeditious revascularization 1
• Debride all hyperkeratosis (callus) and necrotic tissue before assessment, except in non-infected ulcers with severe ischemia 2
• Obtain tissue specimens by biopsy, ulcer curettage, or aspiration (preferred over swabs) before starting antibiotics 3
• Plain radiography should be obtained in all cases to detect osteomyelitis, foreign bodies, gas in tissues, and Charcot deformity 2

Interdisciplinary Team Composition

The team should include specialists skilled in endovascular revascularization, surgical revascularization, wound healing therapies, foot surgery, and medical care 1:

• Vascular medicine and surgery specialists
• Interventional radiology and cardiology
• Orthopedic surgeons and podiatrists
• Infectious disease specialists
• Endocrinologists
• Wound care nurses
• Physical medicine and rehabilitation clinicians 1

Preventive Care Requirements

Patient Education (Class I Recommendation)

• Counsel all patients with PAD and diabetes about self-foot examination and healthy foot behaviors 1
• Teach daily foot inspection (visual or with unbreakable mirror for those who cannot see their feet) 1
• Instruct on proper foot hygiene: wash daily with soap and water, dry thoroughly between toes 4, 5
• Emphasize avoidance of barefoot walking both indoors and outdoors 4, 5
• Always wear shoes with socks—never wear shoes without socks 4, 5
• Inspect inside of shoes daily before wearing to detect potential irritants 4, 5
• Apply lubricating creams for dry skin but never between the toes (increases maceration and infection risk) 4, 5
• Seek immediate medical attention for new foot problems 1

Clinical Examination Schedule

• Perform biannual (every 6 months) foot examination for patients with PAD and diabetes 1
• Inspect feet at every visit for patients with evidence of sensory loss, prior ulceration, or amputation 1
• Examination includes: visual inspection for ulcers and structural deformities, monofilament testing, pulse palpation, and assessment for bony abnormalities 1

Footwear Management

• Prescribe custom therapeutic footwear for high-risk patients with significant neuropathy, foot deformities, or previous amputation 6
• Wear loose-fitting shoes with roomy cotton socks and padded slippers to avoid pressure points 4
• Patients with extreme bony deformities (e.g., Charcot foot) may need custom-molded shoes 1
• Change socks at least once daily and avoid tight or knee-high socks 5

Revascularization Considerations

Indications for Vascular Intervention

• Revascularization (endovascular or surgical bypass) is recommended for patients with DFU and PAD 6
• Severe ischemia with ABI <0.5 or ankle pressure <50 mmHg requires urgent intervention 2
• If wound does not improve within 6 weeks despite optimal management, consider vascular imaging and revascularization regardless of bedside test results 2
• Pentoxifylline can improve function and symptoms in intermittent claudication but is not intended to replace definitive surgical therapy 7

High-Risk Patient Management

Patients Requiring Intensified Care

• Refer patients who smoke with history of prior lower-extremity complications, loss of protective sensation, structural abnormalities, or PAD to foot care specialists for ongoing preventive care and lifelong surveillance 1
• Patients on dialysis, those with Charcot foot, history of prior ulcers/amputation require multidisciplinary approach 1
• History of foot ulcers, infections, or amputation identifies patients with >10% yearly incidence of recurrent ulcers 1

Adjunctive Therapies for Non-Healing Wounds

• For DFUs failing to improve (>50% wound area reduction) after minimum 4 weeks of standard therapy, consider adjunctive wound therapy options 6
• Granulocyte colony-stimulating factors and systemic hyperbaric oxygen therapy may help prevent amputations in severe infections 3

Critical Pitfalls to Avoid

• Do not attribute poor healing to "diabetic microangiopathy"—always assess for correctable vascular insufficiency 2
• Patients with PAD and infection are at high risk for major amputation and require emergency treatment 2
• Never use chemical agents or plasters to remove corns and calluses—seek professional care 5
• Avoid heating devices to warm feet (increases moisture and infection risk) 5
• Monitor patients on warfarin more frequently when starting pentoxifylline due to increased prothrombin time 7